It is widely understood that the occlusion of the left atrial appendage of the human heart will prevent strokes. The mechanism of action is that clots present within the left atrial appendage can become entrained into the general circulation and be transported to the brain where the clots can occlude arterial vessels causing an ischemic stroke.
Devices that have received significant clinical study include the “Plaato” device described in U.S. Pat. No. 6,152,144 among others, and the “Watchman” device described in U.S. Pat. No. 6,689,150 among others. Each of these clinically tested devices lies wholly within the left atrial appendage and includes a membrane that spans the opening or ostium of the left atrial appendage. The Watchman device is typically porous and in the Plaato device the membrane is impervious to the passage of blood. Additionally, the Watchman device uses a series of barbs or prongs which enter the tissue surrounding the ostium of the left atrial appendage to help secure the device during the acute phase of implant.
Although both of these devices appear to be successful, they each have shortcomings and drawbacks, which suggest that additional development is required for a widely acceptable and successful left atrial appendage device.